Osteitis in Systemic Sclerosis: a nationwide case-control retrospective study (SCLEROS Study)

Objective Systemic sclerosis (SSc) is an autoimmune (AI) connective tissue disorder characterized by skin fibrosis, vasculopathy and dysimmunity. Data regarding osteitis in SSc are scarce. Method We performed a nationwide multicentre retrospective case-control study including patients with SSc according to the 2013 ACR/EULAR classification, with a diagnosis of osteitis. The objectives of the study were to describe, to characterize, and to identify associated factors for osteitis in patients with SSc. Results Forty-eight patients were included. Twenty-six patients (54.1%) had osteitis beneath digital tip ulcers. Physical symptoms included: pain (36/48, 75%), erythema (35/48, 73%), and local warmth (35/48, 73%). Thirty-one (65%) patients had C-reactive protein levels >2 mg/L (8 [2.7 - 44.3] mg/L). On X-ray, CT-scans or MRI, osteitis was characterized by swelling or abscess of soft tissues with acro-osteolysis or lysis in 28 patients (58%). Microbiological sampling was performed in 45 (94%) patients. Most pathogens were Staphylococcus aureus (43.8%); anaerobes and Enterobacteriaceae (29.1%) and Pseudomonas aeruginosa (10.4%). Management comprised antibiotics in 37 (77.1%) patients and/or surgery in 26 (54.2%). Fluoroquinolones were used in 22 (45.8%) patients and amoxicillin + beta-lactamase inhibitor in 7 (14.6%). Six (12.6%) patients relapsed, 6 (12.6%) patients had osteitis recurrence, 15 (32%) sequelae, and 2 patients had septic shock and died. Conclusion This study confirmed digital tip ulcers as an associated factor for osteitis, and revealed a high rate of functional sequelae. Antimicrobial therapy with oral fluoroquinolone or intravenous amoxicillin and beta-lactamase inhibitor are used as first-line antibiotherapy in SSc patients with osteitis.